Move remaining sequential tool functionality to multi-core tool

[Meijuh]

pins2lts-mc.c contains rudimentary support for LTS storage (full vectors) en POR (alleen stack proviso)

To eliminate the sequential tool, we have to: add the color/queue proviso in the multi-core tool distinguish state revisiting algorithms (NDFSs) and limit their combination with POR to single threaded cases only write LTSs in index format (extend PBFS with local resizing hash/tree tables and transition communication) Th SCC algorithm will be lost, but more efficient versions are available for the multi-core tool in a local branch